Storage control devices include a plurality of storage devices. Redundant storage areas are formed based on RAID (Redundant Array of Independent Disks), using the physical storage areas of each storage device. Logical volumes formed in the redundant storage areas are provided to host computers, via communication networks, or the like.
Hard disk drives are normally used as the storage device. This is because hard disk drives have superior cost performance. In a hard disk drive, data is read or written by bringing a magnetic head close to a disk rotating at high speed. In a hard disk drive, the higher the rotation speed, the faster the data can be read and written. Therefore, it is necessary to increase the number of revolutions of the hard disk drive in a specific time, and increase the rotation accuracy.
Storage control devices include a plurality of storage devices (normally a large number). When each storage device is started and each disk rotates at high speed, the vibrations produced in each storage device interfere at specific time intervals. If large vibrations are produced by the interference, read errors or write errors occur within the storage devices, so the performance of the storage control device is reduced.
A first conventional technology (Patent Literature 1) for preventing resonance by making the natural frequency of an optical disk and the rotation speed of the spindle of a spindle motor different, by setting the target rotation speed of the spindle motor in accordance with the type of optical disk is well known.
A second conventional technology (Patent Literature 2) in which at least one of the diameter of the shaft of the spindle motor, the shaft material, the bearing size supporting the shaft, the disk thickness, the disk material, the disk clamping position, and the disk clamping force is adjusted in order to adjust the mechanical resonance frequency of the hard disk drive is also well known.
A third conventional technology in which the weight of the hard disk drive, the suspension spring constant, and the suspension damping constant are selected in order to make the resonance characteristics of the plurality of hard disk drives different from each other is also well known.